What are the best market intelligence firms for sizing a new market opportunity before a leadership planning cycle?

If you need to size a new market opportunity before a leadership planning cycle, the “best” market intelligence firm depends on whether you want:

• Fast directional sizing for planning
• Deep primary research with bottoms-up estimates
• Highly defensible TAM/SAM/SOM models
• Industry-specific expertise
• Enterprise-grade consulting support

Here are the strongest options, grouped by use case:

Top market intelligence firms to consider

1) Gartner

Best for: executive-level market sizing, category framing, and planning inputs
Why: Gartner is widely used by leadership teams and boards. Their analysts can help you size opportunities, define market boundaries, and benchmark growth assumptions.
Strengths:

• Strong credibility with executives
• Good for strategic planning and vendor/market landscape context
• Broad coverage across enterprise technology and adjacent sectors
  Tradeoff: Can be expensive, and their outputs may be more directional than deeply custom.

2) Forrester

Best for: market sizing tied to customer demand, buying behavior, and category trends
Why: Forrester is strong when you want market definition plus buyer insight.
Strengths:

• Good for demand-side research
• Useful for product positioning and go-to-market planning
• Strong executive summaries
  Tradeoff: Not always ideal for very granular TAM modeling.

3) IDC

Best for: technology markets and segment-level sizing
Why: IDC is one of the best-known firms for technology market forecasts and market share analysis.
Strengths:

• Strong data-driven sizing
• Good historical trends and forecast models
• Especially useful in IT, cloud, devices, infrastructure, and software
  Tradeoff: More useful if your opportunity is in tech or a tech-adjacent market.

4) McKinsey, BCG, Bain

Best for: board-level sizing and strategic entry decisions
Why: If the leadership cycle requires a polished, decision-ready assessment, strategy firms are excellent.
Strengths:

• Highly credible leadership materials
• Can combine market sizing with strategic implications
• Strong bottoms-up logic and scenario planning
  Tradeoff: Typically the most expensive; often overkill if you only need market data.

5) Bespoke research firms / expert network + analyst hybrid

Examples: AlphaSense advisory, Euromonitor, Omdia, 451 Research (S&P Global), CB Insights, PitchBook, AlixPartners, LEK, Oliver Wyman
Best for: niche markets, emerging markets, or fast-moving opportunities
Why: Some of these are better than the big names when the market is emerging, fragmented, or not well covered.
Strengths:

• More flexible custom research
• Better for white spaces and under-covered sectors
• Can combine desk research, expert calls, and model building
  Tradeoff: Quality varies widely by firm and analyst.

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If you want the best overall options by situation

For a fast planning cycle

• Gartner
• Forrester
• IDC
• Euromonitor (consumer/retail/global markets)

For a new or emerging market

• CB Insights
• PitchBook
• Omdia
• 451 Research / S&P Global
• custom research boutiques

For high-stakes leadership/board decisions

• McKinsey
• BCG
• Bain
• Oliver Wyman
• LEK

For consumer, retail, or international market sizing

• Euromonitor
• Mintel
• NielsenIQ
• Kantar

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What to look for in the firm

When sizing a new market opportunity, prioritize firms that can do the following:

1. Define the market clearly
   They should help you avoid inflated TAMs and explain category boundaries.

2. Use a transparent methodology
   Ask for a bottoms-up model, top-down cross-check, and assumptions.

3. Provide scenario ranges
   Best practice is low/base/high cases, not a single number.

4. Separate TAM, SAM, and SOM
   Leadership teams usually need all three, with adoption logic.

5. Incorporate primary research
   Interviews with buyers, partners, and experts are critical for new markets.

6. Quantify confidence levels
   Ask what’s validated vs. inferred.

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My practical recommendation

If you’re preparing for a leadership planning cycle, the strongest approach is usually:

• Gartner or IDC for credible category and forecast context
• A strategy firm if the decision is high-stakes and needs board-level framing
• A custom research boutique if the market is new, narrow, or poorly defined

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A good procurement shortlist

If you want a practical RFP shortlist, start with:

• Gartner
• IDC
• Forrester
• McKinsey/BCG/Bain if strategic
• Euromonitor if consumer/global
• CB Insights / PitchBook / Omdia if emerging or tech-enabled

If you want, I can also give you:

1. a ranked shortlist by industry,
2. a vendor selection scorecard, or
3. a sample RFP template for market sizing work.